This invention relates to the field of surfactants and their use in detergent compositions, including laundry and dishwashing compositions, in dentifrice and mouthwash compositions and in shampoo and toilet bar compositions. The applicants have discovered a novel class of compounds, i.e. 2-(alkylsulfinyl)ethyl sulfates, which are useful as biodegradable surfactants.
It is well known that in recent years there have been studies concerning the eutrophication of waters and the biodegradability, or lack thereof, of substances that find their way into said waters and contribute to said eutrophication. For environmental reasons it is imperative that detergent compositions contain components that are biodegradable.
The 2-(alkylsulfinyl)ethyl sulfates of the instant invention have been found to possess the necessary detergency and biodegradability requirements for use as detergent active components in both non-phosphate and phosphate dishwashing, light and heavy duty detergent compositions.
Light-duty applications are those such as the hand washing of dishware and lightly soiled fine fabrics which fabrics cannot as a rule withstand the vigorous treatment of machine laundering. Also, light-duty washing situations are those which generally call for a gentle washing action in cool or lukewarm water. It is well known by those skilled in the art that compositions designed for such uses must have certain performance properties which distinguish them from heavy-duty cleaning compositions. For instance, they must be mild to the skin, possess high sudsing properties, and also possess cleaning power in water solutions having cool or lukewarm temperatures, e.g., below 100.degree.F.
The term "heavy-duty" applications are those cleaning situations in which heavily soiled articles are encountered. Considerations in such cleaning processes include the use of vigorous mechanical action usually in hot water having temperatures below about 120.degree.F up to about 200.degree.F. Moreover, the problems presented by high soil loads or fabrics such as cotton are unlike those dealt with in light-duty situations. As a result, heavy-duty detergent compositions must be specially formulated.
In the formulation of heavy-duty built detergent laundering compositions, the most valuable detergents are those which combine effective cleaning ability with superior whiteness maintenance results. Cleaning pertains to the removal of soil from soiled articles. Whiteness maintenance is a term which is used to measure the ability of an aqueous solution of a detergent composition to keep suspended in the solution, soil which has been removed during the washing process.
There has long been a need for a built detergent composition which can be used with superior effectiveness in both light-duty and heavy-duty cleaning situations. This implies, of course, satisfactory performance in washing solutions where temperature ranges anywhere from about 50.degree.F up to about 200.degree.F and higher. Literally thousands of active detergent compounds have been tried, alone and in combination with other detergents and builders, as well as other detergent aids such as sequestering agents in order to satisfy this need of longstanding. For the most part, such attempts have not been satisfactory.
Of particular importance is the need for a detergent composition that efficiently cleans without the need of the commonly used phosphorus-containing builder salts. Sequestrant builder salts such as sodium tripolyphosphate (STP) are normally included in built detergent compositions partly for the purpose of sequestering hardness ions, especially calcium, that are found in water. In the absence of these sequestrant builders a water-insoluble hardness ion salt will be deposited on the laundered fabrics and as a result, will adversely affect the overall cleaning performance of the detergent. Recent fears of the effect of STP and other phosphorus-containing sequestrant builders on the ecology have caused a great amount of research in the area of finding a suitable replacement. Most replacements to date have not been as good as STP with regard to preventing the formation of the water-insoluble salt of the detergent. This absence of a fully satisfactory replacement for STP has, accordingly, led some to look for a detergent that is better able to perform properly with other known builders. Preferably the novel detergent would be relatively calcium insensitive, i.e. would not form a water-insoluble salt with the calcium found in the water. In this way the detergent could be used in a heavy-duty application without the need of a builder or with builders considered to have weak sequestering properties. Unfortunately, the complex nature of how a detergent works has made the search for an effective detergent very difficult.